TLV62130: Inverting power supply circuit

Hi Jeffrey,

What is the input voltage (MAIN_P) and load current on the -2.5V rail?

Can you share the part numbers for the caps C3, C7, C9, C52, and C40? Their case size looks quite small for the capacitance listed, so their DC bias performance is likely quite poor.

You can try adding more output capacitance to solve the ripple on the -2.5V rail.

Hi Chris,

The designed output voltage of inverting power supply circuit is not -2.5V but -5V.

Please refer to the below comments that you asked me.
1. Input voltage and load current
MAIN_P=7.4V, load current=40mA
2. Capacitors P/N
C9, C52 : 1005 size, 10uF, X5R
C26 : 1005 size, 100nF, C0G
C31 : 1005 size, 3.3nF, C0G
C40 : 1608 size, 22uF, X5R

I'm trying to change the capacitor size from 1005 to 2012(C9/C52), 1005 to 1608(C26, C31), and 1608 to 2012(C40).

Regards,
Jeffrey

Hi Chris,

I tried to change the capacitor size like previous reply, and tried to add more output capacitance like your comment.
But there was no improvement on this issue, and it was just same.
Please let me know how to resolve that.

Regards,
Jeffrey

Hi Jeffrey,

Thanks for testing this possibility and for pointing out the error in the output voltage which I confused initially.

Can you post your PCB layout? You might also try reducing the FB resistor value by 10x each to make it more robust to noise.

On the capacitors, the actual part numbers are needed. The DC bias performance differs with the exact part number, so that different 10uF caps perform differently.